#include <xcb/xcb.h>
#include <xcb/randr.h>
#include "dat.h"
#include "fn.h"

static xcb_connection_t *conn;
static xcb_screen_t *scr;
static xcb_window_t win;
static xcb_gcontext_t gc;
static xcb_pixmap_t pix;
static u32int *img;
static xcb_atom_t currentdesktop;
static xcb_atom_t workarea;
static int depth, hasrandr, imgh, imgw;

static xcb_screen_t*
getscr(xcb_connection_t *c, int n)
{
	xcb_screen_iterator_t i;

	for(i = xcb_setup_roots_iterator(xcb_get_setup(c)); i.rem; xcb_screen_next(&i))
		if(n-- == 0)
			return i.data;
	return nil;
}

static xcb_visualtype_t*
getvisual(xcb_screen_t *s)
{
	xcb_depth_iterator_t di;
	xcb_visualtype_iterator_t vi;

	for(di = xcb_screen_allowed_depths_iterator(s); di.rem;
	    xcb_depth_next(&di)){
		if(di.data->depth != s->root_depth)
			continue;
		for(vi = xcb_depth_visuals_iterator(di.data); vi.rem;
		    xcb_visualtype_next(&vi))
			if(vi.data->visual_id == s->root_visual)
				return vi.data;
	}
	return nil;
}

static int
validformat(xcb_connection_t *c, xcb_screen_t *s)
{
	const xcb_setup_t *setup;
	xcb_format_iterator_t fi;
	xcb_visualtype_t *v;
	u32int one;
	int lsb;

	setup = xcb_get_setup(c);
	v = getvisual(s);
	if(v == nil || s->root_depth != 24 ||
	   v->_class != XCB_VISUAL_CLASS_TRUE_COLOR ||
	   v->red_mask != 0xff0000 || v->green_mask != 0x00ff00 ||
	   v->blue_mask != 0x0000ff)
		return 0;
	one = 1;
	lsb = *(uchar*)&one != 0;
	if((lsb && setup->image_byte_order != XCB_IMAGE_ORDER_LSB_FIRST) ||
	   (!lsb && setup->image_byte_order != XCB_IMAGE_ORDER_MSB_FIRST))
		return 0;
	for(fi = xcb_setup_pixmap_formats_iterator(setup); fi.rem;
	    xcb_format_next(&fi))
		if(fi.data->depth == 24 && fi.data->bits_per_pixel == 32 &&
		   fi.data->scanline_pad == 32)
			return 1;
	return 0;
}

static xcb_atom_t
getatom(char *name, int exists)
{
	xcb_intern_atom_cookie_t cookie;
	xcb_intern_atom_reply_t *reply;
	xcb_atom_t atom;

	cookie = xcb_intern_atom(conn, exists, strlen(name), name);
	reply = xcb_intern_atom_reply(conn, cookie, nil);
	atom = reply == nil ? XCB_ATOM_NONE : reply->atom;
	free(reply);
	return atom;
}

static int
getcardinals(xcb_atom_t atom, u32int off, int n, u32int *v)
{
	xcb_get_property_cookie_t cookie;
	xcb_get_property_reply_t *reply;
	int ok;

	if(atom == XCB_ATOM_NONE)
		return 0;
	cookie = xcb_get_property(conn, 0, scr->root, atom,
		XCB_ATOM_CARDINAL, off, n);
	reply = xcb_get_property_reply(conn, cookie, nil);
	ok = reply != nil && reply->type == XCB_ATOM_CARDINAL &&
		reply->format == 32 &&
		xcb_get_property_value_length(reply) == n*(int)sizeof v[0];
	if(ok)
		memmove(v, xcb_get_property_value(reply), n*sizeof v[0]);
	free(reply);
	return ok;
}

static int
getworkarea(Area *a)
{
	u32int desktop, v[4];

	if(!getcardinals(currentdesktop, 0, 1, &desktop) ||
	   desktop > 0x3fffffff ||
	   !getcardinals(workarea, desktop*4, 4, v) ||
	   v[0] > 0x7fffffff || v[1] > 0x7fffffff ||
	   v[2] == 0 || v[2] > 0x7fffffff ||
	   v[3] == 0 || v[3] > 0x7fffffff)
		return 0;
	a->x = v[0];
	a->y = v[1];
	a->w = v[2];
	a->h = v[3];
	return 1;
}

static void
getrootarea(Area *a)
{
	xcb_get_geometry_cookie_t cookie;
	xcb_get_geometry_reply_t *reply;

	a->x = 0;
	a->y = 0;
	a->w = scr->width_in_pixels;
	a->h = scr->height_in_pixels;
	cookie = xcb_get_geometry(conn, scr->root);
	reply = xcb_get_geometry_reply(conn, cookie, nil);
	if(reply != nil && reply->width > 0 && reply->height > 0){
		a->w = reply->width;
		a->h = reply->height;
	}
	free(reply);
}

static void
popupwork(int x, int y, Area *out)
{
	xcb_generic_error_t *err;
	xcb_randr_get_monitors_cookie_t cookie;
	xcb_randr_get_monitors_reply_t *reply;
	xcb_randr_monitor_info_iterator_t it;
	Area root, net, *mon;
	int i, j, n;

	mon = nil;
	n = 0;
	err = nil;
	reply = nil;
	if(hasrandr){
		cookie = xcb_randr_get_monitors(conn, scr->root, 1);
		reply = xcb_randr_get_monitors_reply(conn, cookie, &err);
		if(reply != nil)
			n = xcb_randr_get_monitors_monitors_length(reply);
		if(n > 0 && (uvlong)n <= (uvlong)(~(ulong)0)/sizeof mon[0])
			mon = malloc(n*sizeof mon[0]);
		if(mon != nil){
			it = xcb_randr_get_monitors_monitors_iterator(reply);
			for(i = j = 0; i < n && it.rem; i++, xcb_randr_monitor_info_next(&it)){
				if(it.data->width == 0 || it.data->height == 0)
					continue;
				mon[j].x = it.data->x;
				mon[j].y = it.data->y;
				mon[j].w = it.data->width;
				mon[j].h = it.data->height;
				j++;
			}
			n = j;
			if(n == 0){
				free(mon);
				mon = nil;
			}
		}
	}
	if(mon == nil){
		getrootarea(&root);
		mon = &root;
		n = 1;
	}
	if(getworkarea(&net))
		popuparea(mon, n, &net, x, y, out);
	else
		popuparea(mon, n, nil, x, y, out);
	if(mon != &root)
		free(mon);
	free(reply);
	free(err);
}

static void
wincleanup(void)
{
	textclose();
	free(img);
	img = nil;
	if(conn != nil){
		xcb_disconnect(conn);
		conn = nil;
	}
	scr = nil;
	win = 0;
	gc = 0;
	pix = 0;
	currentdesktop = XCB_ATOM_NONE;
	workarea = XCB_ATOM_NONE;
	hasrandr = 0;
	imgh = 0;
	imgw = 0;
}

static int
wininit(void)
{
	int n;
	u32int mask, vals[4];
	xcb_intern_atom_cookie_t c1, c2;
	xcb_intern_atom_reply_t *r1, *r2;
	xcb_randr_query_version_cookie_t rc;
	xcb_randr_query_version_reply_t *rr;
	const xcb_query_extension_reply_t *rext;

	conn = xcb_connect(nil, &n);
	if(conn == nil || xcb_connection_has_error(conn)){
		fprint(2, "strans: popup disabled: cannot connect to X display\n");
		wincleanup();
		return 0;
	}
	scr = getscr(conn, n);
	if(scr == nil || !validformat(conn, scr)){
		fprint(2, "strans: popup disabled: unsupported X root format\n");
		wincleanup();
		return 0;
	}
	depth = scr->root_depth;
	rext = xcb_get_extension_data(conn, &xcb_randr_id);
	if(rext != nil && rext->present){
		rc = xcb_randr_query_version(conn, 1, 5);
		rr = xcb_randr_query_version_reply(conn, rc, nil);
		hasrandr = rr != nil && (rr->major_version > 1 ||
			(rr->major_version == 1 && rr->minor_version >= 5));
		free(rr);
	}
	currentdesktop = getatom("_NET_CURRENT_DESKTOP", 0);
	workarea = getatom("_NET_WORKAREA", 0);
	win = xcb_generate_id(conn);
	mask = XCB_CW_BACK_PIXEL | XCB_CW_BORDER_PIXEL |
	       XCB_CW_OVERRIDE_REDIRECT | XCB_CW_SAVE_UNDER;
	vals[0] = Colbg;
	vals[1] = 0;
	vals[2] = 1;
	vals[3] = 1;
	xcb_create_window(conn, XCB_COPY_FROM_PARENT, win, scr->root,
		0, 0, 1, 1, 0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
		scr->root_visual, mask, vals);
	c1 = xcb_intern_atom(conn, 0,
		strlen("_NET_WM_WINDOW_TYPE"), "_NET_WM_WINDOW_TYPE");
	c2 = xcb_intern_atom(conn, 0,
		strlen("_NET_WM_WINDOW_TYPE_TOOLTIP"),
		"_NET_WM_WINDOW_TYPE_TOOLTIP");
	r1 = xcb_intern_atom_reply(conn, c1, nil);
	r2 = xcb_intern_atom_reply(conn, c2, nil);
	if(r1 != nil && r2 != nil)
		xcb_change_property(conn, XCB_PROP_MODE_REPLACE,
			win, r1->atom, XCB_ATOM_ATOM, 32, 1, &r2->atom);
	free(r1);
	free(r2);
	gc = xcb_generate_id(conn);
	xcb_create_gc(conn, gc, win, 0, nil);
	if(!textinit()){
		fprint(2, "strans: popup disabled: no usable fonts\n");
		wincleanup();
		return 0;
	}
	return 1;
}

static int
resizebacking(int w, int h)
{
	xcb_generic_error_t *err;
	xcb_pixmap_t old, new;
	xcb_void_cookie_t cookie;
	uvlong pixels;
	int nh, nw;

	if(w <= 0 || h <= 0)
		return 0;
	if(w <= imgw && h <= imgh)
		return 1;
	nw = max(w, imgw);
	nh = max(h, imgh);
	pixels = (uvlong)nw * nh;
	if(pixels > (uvlong)(~(ulong)0)/sizeof img[0])
		return 0;
	img = erealloc(img, pixels*sizeof img[0]);
	new = xcb_generate_id(conn);
	cookie = xcb_create_pixmap_checked(conn, depth, new, win, nw, nh);
	err = xcb_request_check(conn, cookie);
	if(err != nil){
		free(err);
		return 0;
	}
	cookie = xcb_change_window_attributes_checked(conn, win,
		XCB_CW_BACK_PIXMAP, &new);
	err = xcb_request_check(conn, cookie);
	if(err != nil){
		free(err);
		xcb_free_pixmap(conn, new);
		return 0;
	}
	old = pix;
	pix = new;
	imgw = nw;
	imgh = nh;
	if(old != 0)
		xcb_free_pixmap(conn, old);
	return 1;
}

static void
putimage(int w, int h)
{
	if(w <= 0 || w > imgw || h <= 0 || h > imgh)
		return;
	xcb_put_image(conn, XCB_IMAGE_FORMAT_Z_PIXMAP, pix, gc,
		w, h, 0, 0, 0, depth, w * h * 4, (u8int*)img);
	/* The retained background pixmap lets the server repaint exposures. */
	xcb_clear_area(conn, 0, win, 0, 0, w, h);
}

static int
winhide(void)
{
	xcb_unmap_window(conn, win);
	return xcb_flush(conn) > 0;
}

static int
winshow(Drawcmd *dc)
{
	Area area;
	Popup p;
	int ax, ay, px, py;
	u32int vals[4];
	xcb_query_pointer_reply_t *ptr;
	xcb_query_pointer_cookie_t cookie;

	if(dc->nkouho <= 0 && dc->pre.n == 0){
		return winhide();
	}
	px = py = 0;
	if(!dc->caret.valid){
		cookie = xcb_query_pointer(conn, scr->root);
		ptr = xcb_query_pointer_reply(conn, cookie, nil);
		if(ptr == nil)
			return 0;
		px = ptr->root_x;
		py = ptr->root_y;
		free(ptr);
	}
	ax = dc->caret.valid ? dc->caret.x : px;
	ay = dc->caret.valid ? dc->caret.y : py;
	popupwork(ax, ay, &area);
	popuplayout(dc, area.w, area.h, &p);
	if(p.w <= 0 || p.h <= 0 || !resizebacking(p.w, p.h))
		return 0;
	vals[2] = p.w;
	vals[3] = p.h;
	popupposition(&dc->caret, px, py, &area, p.w, p.h, &px, &py);
	vals[1] = py;
	vals[0] = px;
	xcb_configure_window(conn, win,
		XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y |
		XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT,
		vals);
	popupdraw(img, dc, &p);
	putimage(p.w, p.h);
	xcb_map_window(conn, win);
	return xcb_flush(conn) > 0;
}

void
drawthread(void*)
{
	Drawcmd dc;

	threadsetname("draw");
	if(!wininit())
		return;
	while(chanrecv(drawc, &dc) > 0){
		while(channbrecv(drawc, &dc) > 0)
			;
		if(dc.nkouho == 0 && dc.pre.n == 0){
			if(!winhide())
				break;
		}else if(!winshow(&dc))
			break;
	}
	wincleanup();
}